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<FONT color="green">001</FONT>    package project3.lex;<a name="line.1"></a>
<FONT color="green">002</FONT>    <a name="line.2"></a>
<FONT color="green">003</FONT>    import java.io.StringReader;<a name="line.3"></a>
<FONT color="green">004</FONT>    <a name="line.4"></a>
<FONT color="green">005</FONT>    import project3.three.ParserException;<a name="line.5"></a>
<FONT color="green">006</FONT>    <a name="line.6"></a>
<FONT color="green">007</FONT>    /**<a name="line.7"></a>
<FONT color="green">008</FONT>     * Logically Lex is a sequence of tokens, called "tokens", <a name="line.8"></a>
<FONT color="green">009</FONT>     * where we can look only at the front token or "tokens[0]".<a name="line.9"></a>
<FONT color="green">010</FONT>     *<a name="line.10"></a>
<FONT color="green">011</FONT>     * &lt;p&gt;<a name="line.11"></a>
<FONT color="green">012</FONT>     * Syntax:<a name="line.12"></a>
<FONT color="green">013</FONT>     * &lt;table&gt;<a name="line.13"></a>
<FONT color="green">014</FONT>     *   &lt;tr&gt;<a name="line.14"></a>
<FONT color="green">015</FONT>     *     &lt;td&gt;&lt;b&gt;Lex&lt;/b&gt;&lt;/td&gt;<a name="line.15"></a>
<FONT color="green">016</FONT>     *     &lt;td&gt;&amp;rarr;&lt;/td&gt;<a name="line.16"></a>
<FONT color="green">017</FONT>     *     &lt;td&gt;&lt;b&gt;Token&lt;/b&gt;+&lt;/td&gt;<a name="line.17"></a>
<FONT color="green">018</FONT>     *   &lt;/tr&gt;<a name="line.18"></a>
<FONT color="green">019</FONT>     *   &lt;tr&gt;<a name="line.19"></a>
<FONT color="green">020</FONT>     *     &lt;td&gt;&lt;b&gt;Token&lt;/b&gt;&lt;/td&gt;<a name="line.20"></a>
<FONT color="green">021</FONT>     *     &lt;td&gt;&amp;rarr;&lt;/td&gt;<a name="line.21"></a>
<FONT color="green">022</FONT>     *     &lt;td&gt;&lt;i&gt;Identifier&lt;/i&gt;+ | &lt;i&gt;Constant&lt;/i&gt; | &lt;b&gt;Keyword&lt;/b&gt; |<a name="line.22"></a>
<FONT color="green">023</FONT>     *         &lt;b&gt;Symbol&lt;/b&gt; | &lt;b&gt;Whitespace&lt;/b&gt; | &lt;i&gt;EOF&lt;/i&gt; | &lt;b&gt;Undefined&lt;/b&gt;<a name="line.23"></a>
<FONT color="green">024</FONT>     *     &lt;/td&gt;<a name="line.24"></a>
<FONT color="green">025</FONT>     *   &lt;/tr&gt;<a name="line.25"></a>
<FONT color="green">026</FONT>     *   &lt;tr&gt;<a name="line.26"></a>
<FONT color="green">027</FONT>     *     &lt;td&gt;&lt;i&gt;Identifier&lt;/i&gt;&lt;/td&gt;<a name="line.27"></a>
<FONT color="green">028</FONT>     *     &lt;td&gt;&amp;rarr;&lt;/td&gt;<a name="line.28"></a>
<FONT color="green">029</FONT>     *     &lt;td&gt;&lt;b&gt;Letter&lt;/b&gt; [ &lt;b&gt;Letter&lt;/b&gt; | &lt;b&gt;Digit&lt;/b&gt; ]* &lt;/td&gt;<a name="line.29"></a>
<FONT color="green">030</FONT>     *   &lt;/tr&gt;<a name="line.30"></a>
<FONT color="green">031</FONT>     *   &lt;tr&gt;<a name="line.31"></a>
<FONT color="green">032</FONT>     *     &lt;td&gt;&lt;i&gt;Constant&lt;/i&gt;&lt;/td&gt;<a name="line.32"></a>
<FONT color="green">033</FONT>     *     &lt;td&gt;&amp;rarr;&lt;/td&gt;<a name="line.33"></a>
<FONT color="green">034</FONT>     *     &lt;td&gt;"'" [&lt;b&gt;Non-QuoteCharacter&lt;/b&gt;*<a name="line.34"></a>
<FONT color="green">035</FONT>     *             [["'""'"]+ &lt;b&gt;Non-QuoteCharacter&lt;/b&gt;*]* "'"<a name="line.35"></a>
<FONT color="green">036</FONT>     *     &lt;/td&gt;<a name="line.36"></a>
<FONT color="green">037</FONT>     *   &lt;/tr&gt;<a name="line.37"></a>
<FONT color="green">038</FONT>     *   &lt;tr&gt;<a name="line.38"></a>
<FONT color="green">039</FONT>     *     &lt;td&gt;&lt;b&gt;Keyword&lt;/b&gt;&lt;/td&gt;<a name="line.39"></a>
<FONT color="green">040</FONT>     *     &lt;td&gt;&amp;rarr;&lt;/td&gt;<a name="line.40"></a>
<FONT color="green">041</FONT>     *     &lt;td&gt;"Schemes" | "Facts" | "Rules" | "Queries"&lt;/td&gt;<a name="line.41"></a>
<FONT color="green">042</FONT>     *   &lt;/tr&gt;<a name="line.42"></a>
<FONT color="green">043</FONT>     *   &lt;tr&gt;<a name="line.43"></a>
<FONT color="green">044</FONT>     *     &lt;td&gt;&lt;b&gt;Symbol&lt;/b&gt;&lt;/td&gt;<a name="line.44"></a>
<FONT color="green">045</FONT>     *     &lt;td&gt;&amp;rarr;&lt;/td&gt;<a name="line.45"></a>
<FONT color="green">046</FONT>     *     &lt;td&gt;":" | ":-" | "(" | ")" | "," | "." | "?" &lt;/td&gt;<a name="line.46"></a>
<FONT color="green">047</FONT>     *   &lt;/tr&gt;<a name="line.47"></a>
<FONT color="green">048</FONT>     *   &lt;tr&gt;<a name="line.48"></a>
<FONT color="green">049</FONT>     *     &lt;td valign=top&gt;&lt;b&gt;Whitespace&lt;/b&gt;&lt;/td&gt;<a name="line.49"></a>
<FONT color="green">050</FONT>     *     &lt;td valign=top&gt;&amp;rarr;&lt;/td&gt;<a name="line.50"></a>
<FONT color="green">051</FONT>     *     &lt;td&gt;Horizontal_Tab | Line_Feed | Vertical_Tab | Form_Feed | &lt;br&gt;<a name="line.51"></a>
<FONT color="green">052</FONT>     *         Carriage_Return | File_Separator | Group_Separator | &lt;br&gt;<a name="line.52"></a>
<FONT color="green">053</FONT>     *         Record_Separator | Unit_Separator<a name="line.53"></a>
<FONT color="green">054</FONT>     *     &lt;/td&gt;<a name="line.54"></a>
<FONT color="green">055</FONT>     *   &lt;/tr&gt;<a name="line.55"></a>
<FONT color="green">056</FONT>     *   &lt;tr&gt;<a name="line.56"></a>
<FONT color="green">057</FONT>     *     &lt;td valign=top&gt;&lt;b&gt;Undefined&lt;/b&gt;&lt;/td&gt;<a name="line.57"></a>
<FONT color="green">058</FONT>     *     &lt;td valign=top&gt;&amp;rarr;&lt;/td&gt;<a name="line.58"></a>
<FONT color="green">059</FONT>     *     &lt;td&gt;&lt;i&gt;Any character not defined above&lt;/i&gt; | &lt;br&gt;<a name="line.59"></a>
<FONT color="green">060</FONT>     *         &lt;i&gt;A "-" without a previous ":"&lt;/i&gt; | &lt;br&gt;<a name="line.60"></a>
<FONT color="green">061</FONT>     *         "'" [&lt;b&gt;Non-QuoteCharacter&lt;/b&gt;*<a name="line.61"></a>
<FONT color="green">062</FONT>     *             [["'""'"]+ &lt;b&gt;Non-QuoteCharacter&lt;/b&gt;*]* &lt;i&gt;EOF&lt;/i&gt; <a name="line.62"></a>
<FONT color="green">063</FONT>     *     &lt;/td&gt;<a name="line.63"></a>
<FONT color="green">064</FONT>     *   &lt;/tr&gt;<a name="line.64"></a>
<FONT color="green">065</FONT>     * &lt;/table&gt;<a name="line.65"></a>
<FONT color="green">066</FONT>     * &lt;pre&gt;<a name="line.66"></a>
<FONT color="green">067</FONT>     * Domain Definition:<a name="line.67"></a>
<FONT color="green">068</FONT>     *     tokens : Sequence&amp;lt;Token&amp;gt;<a name="line.68"></a>
<FONT color="green">069</FONT>     *<a name="line.69"></a>
<FONT color="green">070</FONT>     * Instance Invariant:<a name="line.70"></a>
<FONT color="green">071</FONT>     *     |tokens| &amp;gt;= 1 AND<a name="line.71"></a>
<FONT color="green">072</FONT>     *     tokens[|tokens|-1].getTokenType() = TokenType.EOF<a name="line.72"></a>
<FONT color="green">073</FONT>     * &lt;/pre&gt;<a name="line.73"></a>
<FONT color="green">074</FONT>     *<a name="line.74"></a>
<FONT color="green">075</FONT>     * Last Modified: 10 Jan 2006<a name="line.75"></a>
<FONT color="green">076</FONT>     *<a name="line.76"></a>
<FONT color="green">077</FONT>     * @author Scott N. Woodfield<a name="line.77"></a>
<FONT color="green">078</FONT>     * @version 1.0<a name="line.78"></a>
<FONT color="green">079</FONT>     * @see &lt;a href="../../srchtml/lex/Lex.html"&gt;Source Code&lt;/a&gt;<a name="line.79"></a>
<FONT color="green">080</FONT>     */<a name="line.80"></a>
<FONT color="green">081</FONT>    public class Lex<a name="line.81"></a>
<FONT color="green">082</FONT>    {<a name="line.82"></a>
<FONT color="green">083</FONT>    //Domain Implementation<a name="line.83"></a>
<FONT color="green">084</FONT>        // We implement tokens by storeing tokens[0..|tokens-1|] in the variable<a name="line.84"></a>
<FONT color="green">085</FONT>        // file and storing tokens[0] in the one token buffer "token".<a name="line.85"></a>
<FONT color="green">086</FONT>    <a name="line.86"></a>
<FONT color="green">087</FONT>        /**<a name="line.87"></a>
<FONT color="green">088</FONT>         * The "File" we will be reading characters from.  The "File" implements<a name="line.88"></a>
<FONT color="green">089</FONT>         * Lex by holding &lt;i&gt;tokens&lt;/i&gt;[1..|&lt;i&gt;tokens&lt;/i&gt;|-1].<a name="line.89"></a>
<FONT color="green">090</FONT>         * @see &lt;a href="../../srchtml/lex/Lex.html#file"&gt;Source Code&lt;/a&gt;<a name="line.90"></a>
<FONT color="green">091</FONT>         */<a name="line.91"></a>
<FONT color="green">092</FONT>        protected File         file  = null;<a name="line.92"></a>
<FONT color="green">093</FONT>    <a name="line.93"></a>
<FONT color="green">094</FONT>        /**<a name="line.94"></a>
<FONT color="green">095</FONT>         * The front token or &lt;i&gt;tokens&lt;/i&gt;[0].<a name="line.95"></a>
<FONT color="green">096</FONT>         * @see &lt;a href="../../srchtml/lex/Lex.html#token"&gt;Source Code&lt;/a&gt;<a name="line.96"></a>
<FONT color="green">097</FONT>         */<a name="line.97"></a>
<FONT color="green">098</FONT>        protected Token        token = null;<a name="line.98"></a>
<FONT color="green">099</FONT>    <a name="line.99"></a>
<FONT color="green">100</FONT>    //Constructors<a name="line.100"></a>
<FONT color="green">101</FONT>        /**<a name="line.101"></a>
<FONT color="green">102</FONT>         * The default constructor which reads characters from standard input.<a name="line.102"></a>
<FONT color="green">103</FONT>         *<a name="line.103"></a>
<FONT color="green">104</FONT>         * &lt;p&gt;<a name="line.104"></a>
<FONT color="green">105</FONT>         * &lt;table&gt;<a name="line.105"></a>
<FONT color="green">106</FONT>         *   &lt;tr&gt;<a name="line.106"></a>
<FONT color="green">107</FONT>         *     &lt;td valign=top&gt;<a name="line.107"></a>
<FONT color="green">108</FONT>         *       &lt;b&gt;Precondition&lt;/b&gt;:<a name="line.108"></a>
<FONT color="green">109</FONT>         *     &lt;/td&gt;<a name="line.109"></a>
<FONT color="green">110</FONT>         *     &lt;td valign=top&gt;<a name="line.110"></a>
<FONT color="green">111</FONT>         *       first token is syntatically correct<a name="line.111"></a>
<FONT color="green">112</FONT>         *     &lt;/td&gt;<a name="line.112"></a>
<FONT color="green">113</FONT>         *     &lt;td valign=top&gt;<a name="line.113"></a>
<FONT color="green">114</FONT>         *     &lt;/td&gt;<a name="line.114"></a>
<FONT color="green">115</FONT>         *   &lt;/tr&gt;<a name="line.115"></a>
<FONT color="green">116</FONT>         *   &lt;tr&gt;<a name="line.116"></a>
<FONT color="green">117</FONT>         *     &lt;td valign=top&gt;<a name="line.117"></a>
<FONT color="green">118</FONT>         *       &lt;b&gt;Postcondition&lt;/b&gt;:<a name="line.118"></a>
<FONT color="green">119</FONT>         *     &lt;/td&gt;<a name="line.119"></a>
<FONT color="green">120</FONT>         *     &lt;td valign=top&gt;<a name="line.120"></a>
<FONT color="green">121</FONT>         *       file = new File() &lt;br/&gt;<a name="line.121"></a>
<FONT color="green">122</FONT>         *       token = token created by popFront()<a name="line.122"></a>
<FONT color="green">123</FONT>         *     &lt;/td&gt;<a name="line.123"></a>
<FONT color="green">124</FONT>         *     &lt;td valign=top&gt;<a name="line.124"></a>
<FONT color="green">125</FONT>         *       AND &lt;br/&gt;<a name="line.125"></a>
<FONT color="green">126</FONT>         *       &amp;nbsp;<a name="line.126"></a>
<FONT color="green">127</FONT>         *     &lt;/td&gt;<a name="line.127"></a>
<FONT color="green">128</FONT>         *   &lt;/tr&gt;<a name="line.128"></a>
<FONT color="green">129</FONT>         * &lt;/table&gt;<a name="line.129"></a>
<FONT color="green">130</FONT>         *<a name="line.130"></a>
<FONT color="green">131</FONT>         * @throws ParserException if we find an invalid character<a name="line.131"></a>
<FONT color="green">132</FONT>         * @see &lt;a href="../../srchtml/lex/Lex.html#defaultConstructor"&gt;Source Code&lt;/a&gt;<a name="line.132"></a>
<FONT color="green">133</FONT>         */<a name="line.133"></a>
<FONT color="green">134</FONT>        public Lex()<a name="line.134"></a>
<FONT color="green">135</FONT>            throws ParserException<a name="line.135"></a>
<FONT color="green">136</FONT>        {<a name="line.136"></a>
<FONT color="green">137</FONT>            file = new File();<a name="line.137"></a>
<FONT color="green">138</FONT>            popFront();<a name="line.138"></a>
<FONT color="green">139</FONT>        }<a name="line.139"></a>
<FONT color="green">140</FONT>    <a name="line.140"></a>
<FONT color="green">141</FONT>        /**<a name="line.141"></a>
<FONT color="green">142</FONT>         * The constructor which reads characters from a file.<a name="line.142"></a>
<FONT color="green">143</FONT>         *<a name="line.143"></a>
<FONT color="green">144</FONT>         * &lt;p&gt;<a name="line.144"></a>
<FONT color="green">145</FONT>         * &lt;table&gt;<a name="line.145"></a>
<FONT color="green">146</FONT>         *   &lt;tr&gt;<a name="line.146"></a>
<FONT color="green">147</FONT>         *     &lt;td valign=top&gt;<a name="line.147"></a>
<FONT color="green">148</FONT>         *       &lt;b&gt;Precondition&lt;/b&gt;:<a name="line.148"></a>
<FONT color="green">149</FONT>         *     &lt;/td&gt;<a name="line.149"></a>
<FONT color="green">150</FONT>         *     &lt;td valign=top&gt;<a name="line.150"></a>
<FONT color="green">151</FONT>         *       first token is syntatically correct<a name="line.151"></a>
<FONT color="green">152</FONT>         *     &lt;/td&gt;<a name="line.152"></a>
<FONT color="green">153</FONT>         *     &lt;td valign=top&gt;<a name="line.153"></a>
<FONT color="green">154</FONT>         *     &lt;/td&gt;<a name="line.154"></a>
<FONT color="green">155</FONT>         *   &lt;/tr&gt;<a name="line.155"></a>
<FONT color="green">156</FONT>         *   &lt;tr&gt;<a name="line.156"></a>
<FONT color="green">157</FONT>         *     &lt;td valign=top&gt;<a name="line.157"></a>
<FONT color="green">158</FONT>         *       &lt;b&gt;Postcondition&lt;/b&gt;:<a name="line.158"></a>
<FONT color="green">159</FONT>         *     &lt;/td&gt;<a name="line.159"></a>
<FONT color="green">160</FONT>         *     &lt;td valign=top&gt;<a name="line.160"></a>
<FONT color="green">161</FONT>         *       file = new File(fileName) &lt;br/&gt;<a name="line.161"></a>
<FONT color="green">162</FONT>         *       token = token created by popFront()<a name="line.162"></a>
<FONT color="green">163</FONT>         *     &lt;/td&gt;<a name="line.163"></a>
<FONT color="green">164</FONT>         *     &lt;td valign=top&gt;<a name="line.164"></a>
<FONT color="green">165</FONT>         *       AND &lt;br/&gt;<a name="line.165"></a>
<FONT color="green">166</FONT>         *       &amp;nbsp;<a name="line.166"></a>
<FONT color="green">167</FONT>         *     &lt;/td&gt;<a name="line.167"></a>
<FONT color="green">168</FONT>         *   &lt;/tr&gt;<a name="line.168"></a>
<FONT color="green">169</FONT>         * &lt;/table&gt;<a name="line.169"></a>
<FONT color="green">170</FONT>         *<a name="line.170"></a>
<FONT color="green">171</FONT>         * @param fileName the name of the file from which we will read<a name="line.171"></a>
<FONT color="green">172</FONT>         *                 characters.<a name="line.172"></a>
<FONT color="green">173</FONT>         * @see &lt;a href="../../srchtml/lex/Lex.html#StdConstructor"&gt;Source Code&lt;/a&gt;<a name="line.173"></a>
<FONT color="green">174</FONT>         */<a name="line.174"></a>
<FONT color="green">175</FONT>        public Lex(String fileName)<a name="line.175"></a>
<FONT color="green">176</FONT>            throws ParserException<a name="line.176"></a>
<FONT color="green">177</FONT>        {<a name="line.177"></a>
<FONT color="green">178</FONT>            file = new File(fileName);<a name="line.178"></a>
<FONT color="green">179</FONT>            popFront();<a name="line.179"></a>
<FONT color="green">180</FONT>        }<a name="line.180"></a>
<FONT color="green">181</FONT>    <a name="line.181"></a>
<FONT color="green">182</FONT>        /**<a name="line.182"></a>
<FONT color="green">183</FONT>         * The constructor which reads characters from a StringReader.<a name="line.183"></a>
<FONT color="green">184</FONT>         * Used primarily for testing.<a name="line.184"></a>
<FONT color="green">185</FONT>         *<a name="line.185"></a>
<FONT color="green">186</FONT>         * &lt;p&gt;<a name="line.186"></a>
<FONT color="green">187</FONT>         * &lt;table&gt;<a name="line.187"></a>
<FONT color="green">188</FONT>         *   &lt;tr&gt;<a name="line.188"></a>
<FONT color="green">189</FONT>         *     &lt;td valign=top&gt;<a name="line.189"></a>
<FONT color="green">190</FONT>         *       &lt;b&gt;Precondition&lt;/b&gt;:<a name="line.190"></a>
<FONT color="green">191</FONT>         *     &lt;/td&gt;<a name="line.191"></a>
<FONT color="green">192</FONT>         *     &lt;td valign=top&gt;<a name="line.192"></a>
<FONT color="green">193</FONT>         *       first token is syntatically correct<a name="line.193"></a>
<FONT color="green">194</FONT>         *     &lt;/td&gt;<a name="line.194"></a>
<FONT color="green">195</FONT>         *     &lt;td valign=top&gt;<a name="line.195"></a>
<FONT color="green">196</FONT>         *     &lt;/td&gt;<a name="line.196"></a>
<FONT color="green">197</FONT>         *   &lt;/tr&gt;<a name="line.197"></a>
<FONT color="green">198</FONT>         *   &lt;tr&gt;<a name="line.198"></a>
<FONT color="green">199</FONT>         *     &lt;td valign=top&gt;<a name="line.199"></a>
<FONT color="green">200</FONT>         *       &lt;b&gt;Postcondition&lt;/b&gt;:<a name="line.200"></a>
<FONT color="green">201</FONT>         *     &lt;/td&gt;<a name="line.201"></a>
<FONT color="green">202</FONT>         *     &lt;td valign=top&gt;<a name="line.202"></a>
<FONT color="green">203</FONT>         *       file = new File(stringReader) &lt;br/&gt;<a name="line.203"></a>
<FONT color="green">204</FONT>         *       token = token created by popFront()<a name="line.204"></a>
<FONT color="green">205</FONT>         *     &lt;/td&gt;<a name="line.205"></a>
<FONT color="green">206</FONT>         *     &lt;td valign=top&gt;<a name="line.206"></a>
<FONT color="green">207</FONT>         *       AND &lt;br/&gt;<a name="line.207"></a>
<FONT color="green">208</FONT>         *       &amp;nbsp;<a name="line.208"></a>
<FONT color="green">209</FONT>         *     &lt;/td&gt;<a name="line.209"></a>
<FONT color="green">210</FONT>         *   &lt;/tr&gt;<a name="line.210"></a>
<FONT color="green">211</FONT>         * &lt;/table&gt;<a name="line.211"></a>
<FONT color="green">212</FONT>         *<a name="line.212"></a>
<FONT color="green">213</FONT>         * @param stringReader the &lt;b&gt;StringReader&lt;/b&gt; from which we will read<a name="line.213"></a>
<FONT color="green">214</FONT>         *                     characters.<a name="line.214"></a>
<FONT color="green">215</FONT>         * @see &lt;a href="../../srchtml/lex/Lex.html#TestConstructor"&gt;Source Code&lt;/a&gt;<a name="line.215"></a>
<FONT color="green">216</FONT>         */<a name="line.216"></a>
<FONT color="green">217</FONT>        public Lex(StringReader stringReader)<a name="line.217"></a>
<FONT color="green">218</FONT>            throws ParserException<a name="line.218"></a>
<FONT color="green">219</FONT>        {<a name="line.219"></a>
<FONT color="green">220</FONT>            file = new File(stringReader);<a name="line.220"></a>
<FONT color="green">221</FONT>            popFront();<a name="line.221"></a>
<FONT color="green">222</FONT>        }<a name="line.222"></a>
<FONT color="green">223</FONT>    <a name="line.223"></a>
<FONT color="green">224</FONT>    <a name="line.224"></a>
<FONT color="green">225</FONT>    //Queries<a name="line.225"></a>
<FONT color="green">226</FONT>        /**<a name="line.226"></a>
<FONT color="green">227</FONT>         * Returns the front or current token or &lt;b&gt;tokens&lt;/b&gt;[0].<a name="line.227"></a>
<FONT color="green">228</FONT>         *<a name="line.228"></a>
<FONT color="green">229</FONT>         * &lt;p&gt;<a name="line.229"></a>
<FONT color="green">230</FONT>         * &lt;table&gt;<a name="line.230"></a>
<FONT color="green">231</FONT>         *   &lt;tr&gt;<a name="line.231"></a>
<FONT color="green">232</FONT>         *     &lt;td valign=top&gt;<a name="line.232"></a>
<FONT color="green">233</FONT>         *       &lt;b&gt;Precondition&lt;/b&gt;:<a name="line.233"></a>
<FONT color="green">234</FONT>         *     &lt;/td&gt;<a name="line.234"></a>
<FONT color="green">235</FONT>         *     &lt;td valign=top&gt;<a name="line.235"></a>
<FONT color="green">236</FONT>         *       none<a name="line.236"></a>
<FONT color="green">237</FONT>         *     &lt;/td&gt;<a name="line.237"></a>
<FONT color="green">238</FONT>         *     &lt;td valign=top&gt;<a name="line.238"></a>
<FONT color="green">239</FONT>         *     &lt;/td&gt;<a name="line.239"></a>
<FONT color="green">240</FONT>         *   &lt;/tr&gt;<a name="line.240"></a>
<FONT color="green">241</FONT>         *   &lt;tr&gt;<a name="line.241"></a>
<FONT color="green">242</FONT>         *     &lt;td valign=top&gt;<a name="line.242"></a>
<FONT color="green">243</FONT>         *       &lt;b&gt;Postcondition&lt;/b&gt;:<a name="line.243"></a>
<FONT color="green">244</FONT>         *     &lt;/td&gt;<a name="line.244"></a>
<FONT color="green">245</FONT>         *     &lt;td valign=top&gt;<a name="line.245"></a>
<FONT color="green">246</FONT>         *       result = token<a name="line.246"></a>
<FONT color="green">247</FONT>         *     &lt;/td&gt;<a name="line.247"></a>
<FONT color="green">248</FONT>         *     &lt;td valign=top&gt;<a name="line.248"></a>
<FONT color="green">249</FONT>         *     &lt;/td&gt;<a name="line.249"></a>
<FONT color="green">250</FONT>         *   &lt;/tr&gt;<a name="line.250"></a>
<FONT color="green">251</FONT>         * &lt;/table&gt;<a name="line.251"></a>
<FONT color="green">252</FONT>         * @return the front &lt;b&gt;Token&lt;/b&gt;.<a name="line.252"></a>
<FONT color="green">253</FONT>         * @see &lt;a href="../../srchtml/lex/Lex.html#front"&gt;Source Code&lt;/a&gt;<a name="line.253"></a>
<FONT color="green">254</FONT>         */<a name="line.254"></a>
<FONT color="green">255</FONT>        public Token front()<a name="line.255"></a>
<FONT color="green">256</FONT>        {<a name="line.256"></a>
<FONT color="green">257</FONT>            return token;<a name="line.257"></a>
<FONT color="green">258</FONT>        }<a name="line.258"></a>
<FONT color="green">259</FONT>       <a name="line.259"></a>
<FONT color="green">260</FONT>    <a name="line.260"></a>
<FONT color="green">261</FONT>    //Commands<a name="line.261"></a>
<FONT color="green">262</FONT>        /**<a name="line.262"></a>
<FONT color="green">263</FONT>         * Logically this removes the front token (&lt;b&gt;tokens&lt;/b&gt;[0]) from<a name="line.263"></a>
<FONT color="green">264</FONT>         * &lt;b&gt;tokens&lt;/b&gt;. <a name="line.264"></a>
<FONT color="green">265</FONT>         *<a name="line.265"></a>
<FONT color="green">266</FONT>         * &lt;p&gt;<a name="line.266"></a>
<FONT color="green">267</FONT>         * From an implementation point of view, we look at file.front() to<a name="line.267"></a>
<FONT color="green">268</FONT>         * determine which kind of token we are going to create next and then<a name="line.268"></a>
<FONT color="green">269</FONT>         * create it.  Notice that unlike project 1, we ignore whitespace.  Also,<a name="line.269"></a>
<FONT color="green">270</FONT>         * if we find illegal characters, we throw an excpetion rather than return<a name="line.270"></a>
<FONT color="green">271</FONT>         * a token.  Also, there are several tokens which were legal in projects<a name="line.271"></a>
<FONT color="green">272</FONT>         * 1 and 2 but are now illegal.  See the definition of<a name="line.272"></a>
<FONT color="green">273</FONT>         * {@link TokenType TokenType} for a list of these token types.<a name="line.273"></a>
<FONT color="green">274</FONT>         *<a name="line.274"></a>
<FONT color="green">275</FONT>         * &lt;p&gt;<a name="line.275"></a>
<FONT color="green">276</FONT>         * &lt;font size = 1&gt;<a name="line.276"></a>
<FONT color="green">277</FONT>         * &lt;table&gt;<a name="line.277"></a>
<FONT color="green">278</FONT>         *   &lt;tr&gt;<a name="line.278"></a>
<FONT color="green">279</FONT>         *     &lt;td valign=top&gt;<a name="line.279"></a>
<FONT color="green">280</FONT>         *       &lt;font size=3&gt;&lt;b&gt;Precondition&lt;/b&gt;&lt;/font&gt;:<a name="line.280"></a>
<FONT color="green">281</FONT>         *     &lt;/td&gt;<a name="line.281"></a>
<FONT color="green">282</FONT>         *     &lt;td valign=bottom&gt;<a name="line.282"></a>
<FONT color="green">283</FONT>         *       After skipping whitespace, we are at the beginning of a valid<a name="line.283"></a>
<FONT color="green">284</FONT>         *       token.<a name="line.284"></a>
<FONT color="green">285</FONT>         *     &lt;/td&gt;<a name="line.285"></a>
<FONT color="green">286</FONT>         *     &lt;td valign=bottom&gt;<a name="line.286"></a>
<FONT color="green">287</FONT>         *     &lt;/td&gt;<a name="line.287"></a>
<FONT color="green">288</FONT>         *   &lt;/tr&gt;<a name="line.288"></a>
<FONT color="green">289</FONT>         *   &lt;tr&gt;&lt;td&gt;&amp;nbsp&lt;/td&gt;&lt;/tr&gt;<a name="line.289"></a>
<FONT color="green">290</FONT>         *   &lt;tr&gt;<a name="line.290"></a>
<FONT color="green">291</FONT>         *     &lt;td valign=top&gt;<a name="line.291"></a>
<FONT color="green">292</FONT>         *       &lt;font size = 3&gt;&lt;b&gt;Logical Postcondition&lt;/b&gt;&lt;/font&gt;:<a name="line.292"></a>
<FONT color="green">293</FONT>         *     &lt;/td&gt;<a name="line.293"></a>
<FONT color="green">294</FONT>         *     &lt;td valign=bottom&gt;<a name="line.294"></a>
<FONT color="green">295</FONT>         *       |&lt;i&gt;tokens&lt;/i&gt;|  = 1 &amp;rArr;<a name="line.295"></a>
<FONT color="green">296</FONT>         *         (&lt;i&gt;tokens&lt;/i&gt; = &lt;i&gt;tokens'&lt;/i&gt; AND<a name="line.296"></a>
<FONT color="green">297</FONT>         *          &lt;i&gt;tokens&lt;/i&gt;[0].getTokenType() = TokenType.EOF)&lt;br/&gt;<a name="line.297"></a>
<FONT color="green">298</FONT>         *       |&lt;i&gt;tokens&lt;/i&gt;| &amp;ne; 1 &amp;rArr; &lt;i&gt;tokens&lt;/i&gt; =<a name="line.298"></a>
<FONT color="green">299</FONT>         *         &lt;i&gt;tokens'&lt;/i&gt;[1..|&lt;i&gt;tokens'&lt;/i&gt;|-1]<a name="line.299"></a>
<FONT color="green">300</FONT>         *     &lt;/td&gt;<a name="line.300"></a>
<FONT color="green">301</FONT>         *     &lt;td valign=top&gt;<a name="line.301"></a>
<FONT color="green">302</FONT>         *       AND &lt;/br&gt;<a name="line.302"></a>
<FONT color="green">303</FONT>         *       &lt;br/&gt;<a name="line.303"></a>
<FONT color="green">304</FONT>         *     &lt;/td&gt;<a name="line.304"></a>
<FONT color="green">305</FONT>         *   &lt;/tr&gt;<a name="line.305"></a>
<FONT color="green">306</FONT>         *   &lt;tr&gt;&lt;td&gt;&amp;nbsp&lt;/td&gt;&lt;/tr&gt;<a name="line.306"></a>
<FONT color="green">307</FONT>         *   &lt;tr&gt;<a name="line.307"></a>
<FONT color="green">308</FONT>         *     &lt;td valign=middle&gt;<a name="line.308"></a>
<FONT color="green">309</FONT>         *       &lt;font size=3&gt;&lt;b&gt;Implementation Postcondition&lt;/b&gt;&lt;/font&gt;:<a name="line.309"></a>
<FONT color="green">310</FONT>         *     &lt;/td&gt;<a name="line.310"></a>
<FONT color="green">311</FONT>         *     &lt;td valign=bottom&gt;<a name="line.311"></a>
<FONT color="green">312</FONT>         *       file.front() = "'" &amp;rArr; token = getConstant()              &lt;br/&gt;<a name="line.312"></a>
<FONT color="green">313</FONT>         *     &lt;/td&gt;<a name="line.313"></a>
<FONT color="green">314</FONT>         *     &lt;td valign=bottom&gt;<a name="line.314"></a>
<FONT color="green">315</FONT>         *       AND<a name="line.315"></a>
<FONT color="green">316</FONT>         *     &lt;/td&gt;<a name="line.316"></a>
<FONT color="green">317</FONT>         *   &lt;/tr&gt;<a name="line.317"></a>
<FONT color="green">318</FONT>         *   &lt;tr&gt;<a name="line.318"></a>
<FONT color="green">319</FONT>         *     &lt;td&gt;<a name="line.319"></a>
<FONT color="green">320</FONT>         *       &amp;nbsp;<a name="line.320"></a>
<FONT color="green">321</FONT>         *     &lt;/td&gt;<a name="line.321"></a>
<FONT color="green">322</FONT>         *     &lt;td valign=top&gt;<a name="line.322"></a>
<FONT color="green">323</FONT>         *     isLetter(file.front()) &amp;rArr; token = getIdentifierOrKeyword() &lt;br/&gt;<a name="line.323"></a>
<FONT color="green">324</FONT>         *     &lt;/td&gt;<a name="line.324"></a>
<FONT color="green">325</FONT>         *     &lt;td valign=top&gt;<a name="line.325"></a>
<FONT color="green">326</FONT>         *       AND<a name="line.326"></a>
<FONT color="green">327</FONT>         *     &lt;/td&gt;<a name="line.327"></a>
<FONT color="green">328</FONT>         *   &lt;/tr&gt;<a name="line.328"></a>
<FONT color="green">329</FONT>         *   &lt;tr&gt;<a name="line.329"></a>
<FONT color="green">330</FONT>         *     &lt;td&gt;<a name="line.330"></a>
<FONT color="green">331</FONT>         *       &amp;nbsp;<a name="line.331"></a>
<FONT color="green">332</FONT>         *     &lt;/td&gt;<a name="line.332"></a>
<FONT color="green">333</FONT>         *     &lt;td valign=top&gt;<a name="line.333"></a>
<FONT color="green">334</FONT>         *     file.front() = ',' &amp;rArr; token =<a name="line.334"></a>
<FONT color="green">335</FONT>         *         (new (TokenType.COMMA, ",", File'.getLineNumber()) AND<a name="line.335"></a>
<FONT color="green">336</FONT>         *          file = file'.popFront())                                  &lt;br/&gt;<a name="line.336"></a>
<FONT color="green">337</FONT>         *     &lt;/td&gt;<a name="line.337"></a>
<FONT color="green">338</FONT>         *     &lt;td valign=top&gt;<a name="line.338"></a>
<FONT color="green">339</FONT>         *       AND<a name="line.339"></a>
<FONT color="green">340</FONT>         *     &lt;/td&gt;<a name="line.340"></a>
<FONT color="green">341</FONT>         *   &lt;/tr&gt;<a name="line.341"></a>
<FONT color="green">342</FONT>         *   &lt;tr&gt;<a name="line.342"></a>
<FONT color="green">343</FONT>         *     &lt;td&gt;<a name="line.343"></a>
<FONT color="green">344</FONT>         *       &amp;nbsp;<a name="line.344"></a>
<FONT color="green">345</FONT>         *     &lt;/td&gt;<a name="line.345"></a>
<FONT color="green">346</FONT>         *     &lt;td valign=top&gt;<a name="line.346"></a>
<FONT color="green">347</FONT>         *     file.front() = '.' &amp;rArr; token =<a name="line.347"></a>
<FONT color="green">348</FONT>         *         (new (TokenType.PERIOD, ".", File'.getLineNumber()) AND<a name="line.348"></a>
<FONT color="green">349</FONT>         *          file = file'.popFront())                                  &lt;br/&gt;<a name="line.349"></a>
<FONT color="green">350</FONT>         *     &lt;/td&gt;<a name="line.350"></a>
<FONT color="green">351</FONT>         *     &lt;td valign=top&gt;<a name="line.351"></a>
<FONT color="green">352</FONT>         *       AND<a name="line.352"></a>
<FONT color="green">353</FONT>         *     &lt;/td&gt;<a name="line.353"></a>
<FONT color="green">354</FONT>         *   &lt;/tr&gt;<a name="line.354"></a>
<FONT color="green">355</FONT>         *   &lt;tr&gt;<a name="line.355"></a>
<FONT color="green">356</FONT>         *     &lt;td&gt;<a name="line.356"></a>
<FONT color="green">357</FONT>         *       &amp;nbsp;<a name="line.357"></a>
<FONT color="green">358</FONT>         *     &lt;/td&gt;<a name="line.358"></a>
<FONT color="green">359</FONT>         *     &lt;td valign=top&gt;<a name="line.359"></a>
<FONT color="green">360</FONT>         *     file.front() = '(' &amp;rArr; token =<a name="line.360"></a>
<FONT color="green">361</FONT>         *         (new (TokenType.LEFT_PAREN, "(", File'.getLineNumber()) AND<a name="line.361"></a>
<FONT color="green">362</FONT>         *          file = file'.popFront())                                  &lt;br/&gt;<a name="line.362"></a>
<FONT color="green">363</FONT>         *     &lt;/td&gt;<a name="line.363"></a>
<FONT color="green">364</FONT>         *     &lt;td valign=top&gt;<a name="line.364"></a>
<FONT color="green">365</FONT>         *       AND<a name="line.365"></a>
<FONT color="green">366</FONT>         *     &lt;/td&gt;<a name="line.366"></a>
<FONT color="green">367</FONT>         *   &lt;/tr&gt;<a name="line.367"></a>
<FONT color="green">368</FONT>         *   &lt;tr&gt;<a name="line.368"></a>
<FONT color="green">369</FONT>         *     &lt;td&gt;<a name="line.369"></a>
<FONT color="green">370</FONT>         *       &amp;nbsp;<a name="line.370"></a>
<FONT color="green">371</FONT>         *     &lt;/td&gt;<a name="line.371"></a>
<FONT color="green">372</FONT>         *     &lt;td valign=top&gt;<a name="line.372"></a>
<FONT color="green">373</FONT>         *     file.front() = ')' &amp;rArr; token =<a name="line.373"></a>
<FONT color="green">374</FONT>         *         (new (TokenType.RIGHT_PAREN, ")", File'.getLineNumber()) AND<a name="line.374"></a>
<FONT color="green">375</FONT>         *          file = file'.popFront())                                  &lt;br/&gt;<a name="line.375"></a>
<FONT color="green">376</FONT>         *     &lt;/td&gt;<a name="line.376"></a>
<FONT color="green">377</FONT>         *     &lt;td valign=top&gt;<a name="line.377"></a>
<FONT color="green">378</FONT>         *       AND<a name="line.378"></a>
<FONT color="green">379</FONT>         *     &lt;/td&gt;<a name="line.379"></a>
<FONT color="green">380</FONT>         *   &lt;/tr&gt;<a name="line.380"></a>
<FONT color="green">381</FONT>         *   &lt;tr&gt;<a name="line.381"></a>
<FONT color="green">382</FONT>         *     &lt;td&gt;<a name="line.382"></a>
<FONT color="green">383</FONT>         *       &amp;nbsp;<a name="line.383"></a>
<FONT color="green">384</FONT>         *     &lt;/td&gt;<a name="line.384"></a>
<FONT color="green">385</FONT>         *     &lt;td valign=top&gt;<a name="line.385"></a>
<FONT color="green">386</FONT>         *     file.front() = '?' &amp;rArr; token =<a name="line.386"></a>
<FONT color="green">387</FONT>         *         (new (TokenType.Q_MARK, "?", File'.getLineNumber()) AND<a name="line.387"></a>
<FONT color="green">388</FONT>         *          file = file'.popFront())                                  &lt;br/&gt;<a name="line.388"></a>
<FONT color="green">389</FONT>         *     &lt;/td&gt;<a name="line.389"></a>
<FONT color="green">390</FONT>         *     &lt;td valign=top&gt;<a name="line.390"></a>
<FONT color="green">391</FONT>         *       AND<a name="line.391"></a>
<FONT color="green">392</FONT>         *     &lt;/td&gt;<a name="line.392"></a>
<FONT color="green">393</FONT>         *   &lt;/tr&gt;<a name="line.393"></a>
<FONT color="green">394</FONT>         *   &lt;tr&gt;<a name="line.394"></a>
<FONT color="green">395</FONT>         *     &lt;td&gt;<a name="line.395"></a>
<FONT color="green">396</FONT>         *       &amp;nbsp;<a name="line.396"></a>
<FONT color="green">397</FONT>         *     &lt;/td&gt;<a name="line.397"></a>
<FONT color="green">398</FONT>         *     &lt;td valign=top&gt;<a name="line.398"></a>
<FONT color="green">399</FONT>         *     file.front() = ':' &amp;rArr; <a name="line.399"></a>
<FONT color="green">400</FONT>         *         (file[1] = '-' &amp;rArr; token = <a name="line.400"></a>
<FONT color="green">401</FONT>         *            &amp;nbsp;&amp;nbsp;&amp;nbsp;<a name="line.401"></a>
<FONT color="green">402</FONT>         *            (new (TokenType.COLON_DASH, ":-", File'.getLineNumber()) AND<a name="line.402"></a>
<FONT color="green">403</FONT>         *             file = file'.popFront().popFront()) &lt;br/&gt;<a name="line.403"></a>
<FONT color="green">404</FONT>         *          file[1] &amp;ne; '-' &amp;rArr; token = <a name="line.404"></a>
<FONT color="green">405</FONT>         *            &amp;nbsp;&amp;nbsp;&amp;nbsp;<a name="line.405"></a>
<FONT color="green">406</FONT>         *            (new (TokenType.COLON, ":", File'.getLineNumber()) AND<a name="line.406"></a>
<FONT color="green">407</FONT>         *             file = file'.popFront()) <a name="line.407"></a>
<FONT color="green">408</FONT>         *         )                                                          &lt;br/&gt;<a name="line.408"></a>
<FONT color="green">409</FONT>         *     &lt;/td&gt;<a name="line.409"></a>
<FONT color="green">410</FONT>         *     &lt;td valign=top&gt;<a name="line.410"></a>
<FONT color="green">411</FONT>         *       AND<a name="line.411"></a>
<FONT color="green">412</FONT>         *     &lt;/td&gt;<a name="line.412"></a>
<FONT color="green">413</FONT>         *   &lt;/tr&gt;<a name="line.413"></a>
<FONT color="green">414</FONT>         *   &lt;tr&gt;<a name="line.414"></a>
<FONT color="green">415</FONT>         *     &lt;td&gt;<a name="line.415"></a>
<FONT color="green">416</FONT>         *       &amp;nbsp;<a name="line.416"></a>
<FONT color="green">417</FONT>         *     &lt;/td&gt;<a name="line.417"></a>
<FONT color="green">418</FONT>         *     &lt;td valign=top&gt;<a name="line.418"></a>
<FONT color="green">419</FONT>         *     file.front() = File.EOF &amp;rArr;<a name="line.419"></a>
<FONT color="green">420</FONT>         *         new (TokenType.EOF, "", File'.getLineNumber())<a name="line.420"></a>
<FONT color="green">421</FONT>         *     &lt;/td&gt;<a name="line.421"></a>
<FONT color="green">422</FONT>         *     &lt;td valign=top&gt;<a name="line.422"></a>
<FONT color="green">423</FONT>         *       AND<a name="line.423"></a>
<FONT color="green">424</FONT>         *     &lt;/td&gt;<a name="line.424"></a>
<FONT color="green">425</FONT>         *   &lt;/tr&gt;<a name="line.425"></a>
<FONT color="green">426</FONT>         * &lt;/table&gt;<a name="line.426"></a>
<FONT color="green">427</FONT>         * &lt;/font&gt; <a name="line.427"></a>
<FONT color="green">428</FONT>         *<a name="line.428"></a>
<FONT color="green">429</FONT>         * @throws ParserException When we find an invalid character or<a name="line.429"></a>
<FONT color="green">430</FONT>         *                         unterminated string.<a name="line.430"></a>
<FONT color="green">431</FONT>         * @see &lt;a href="../../srchtml/lex/Lex.html#popFront"&gt;Source Code&lt;/a&gt;<a name="line.431"></a>
<FONT color="green">432</FONT>         */<a name="line.432"></a>
<FONT color="green">433</FONT>        public void popFront()<a name="line.433"></a>
<FONT color="green">434</FONT>            throws ParserException<a name="line.434"></a>
<FONT color="green">435</FONT>        {<a name="line.435"></a>
<FONT color="green">436</FONT>            skipWhiteSpace();<a name="line.436"></a>
<FONT color="green">437</FONT>            if(file.front() == file.EOF){  <a name="line.437"></a>
<FONT color="green">438</FONT>                token = new Token(TokenType.EOF, "", file.getLineNumber());<a name="line.438"></a>
<FONT color="green">439</FONT>            } else if(file.front() == '\''){<a name="line.439"></a>
<FONT color="green">440</FONT>                token = getConstant();<a name="line.440"></a>
<FONT color="green">441</FONT>            } else if(Character.isLetter(file.front())){<a name="line.441"></a>
<FONT color="green">442</FONT>                token = getIdentifierOrKeyword();<a name="line.442"></a>
<FONT color="green">443</FONT>            } else if(file.front() == ':'){ //process ":-" or ":'<a name="line.443"></a>
<FONT color="green">444</FONT>                int line = file.getLineNumber();<a name="line.444"></a>
<FONT color="green">445</FONT>                file.popFront();<a name="line.445"></a>
<FONT color="green">446</FONT>                if(file.front() == '-'){<a name="line.446"></a>
<FONT color="green">447</FONT>                    file.popFront();<a name="line.447"></a>
<FONT color="green">448</FONT>                    token = new Token(TokenType.COLON_DASH, ":-", line);<a name="line.448"></a>
<FONT color="green">449</FONT>                } else {<a name="line.449"></a>
<FONT color="green">450</FONT>                    token = new Token(TokenType.COLON, ":", line);<a name="line.450"></a>
<FONT color="green">451</FONT>                };<a name="line.451"></a>
<FONT color="green">452</FONT>            } else { //process single character tokens<a name="line.452"></a>
<FONT color="green">453</FONT>                int line = file.getLineNumber();<a name="line.453"></a>
<FONT color="green">454</FONT>                switch(file.front()){<a name="line.454"></a>
<FONT color="green">455</FONT>                    case ',': token = new Token(TokenType.COMMA, ",", line);<a name="line.455"></a>
<FONT color="green">456</FONT>                              break;<a name="line.456"></a>
<FONT color="green">457</FONT>                    case '.': token = new Token(TokenType.PERIOD, ".", line);<a name="line.457"></a>
<FONT color="green">458</FONT>                              break;<a name="line.458"></a>
<FONT color="green">459</FONT>                    case '(': token = new Token(TokenType.LEFT_PAREN,"(",line);<a name="line.459"></a>
<FONT color="green">460</FONT>                              break;<a name="line.460"></a>
<FONT color="green">461</FONT>                    case ')': token = new Token(TokenType.RIGHT_PAREN,")",<a name="line.461"></a>
<FONT color="green">462</FONT>                                                 line);<a name="line.462"></a>
<FONT color="green">463</FONT>                              break;<a name="line.463"></a>
<FONT color="green">464</FONT>                    case '?': token = new Token(TokenType.Q_MARK, "?", line);<a name="line.464"></a>
<FONT color="green">465</FONT>                              break;<a name="line.465"></a>
<FONT color="green">466</FONT>                    default:  throw new ParserException(<a name="line.466"></a>
<FONT color="green">467</FONT>                                 "Error on line " + line + ".\n" +<a name="line.467"></a>
<FONT color="green">468</FONT>                                  "Invalid character, '" + file.front() + <a name="line.468"></a>
<FONT color="green">469</FONT>                                  "', found.");<a name="line.469"></a>
<FONT color="green">470</FONT>                };<a name="line.470"></a>
<FONT color="green">471</FONT>                file.popFront();<a name="line.471"></a>
<FONT color="green">472</FONT>            };<a name="line.472"></a>
<FONT color="green">473</FONT>        }<a name="line.473"></a>
<FONT color="green">474</FONT>    <a name="line.474"></a>
<FONT color="green">475</FONT>    //Auxillary Methods<a name="line.475"></a>
<FONT color="green">476</FONT>        /**<a name="line.476"></a>
<FONT color="green">477</FONT>         * Skips all of the white space at the beginning of "file".<a name="line.477"></a>
<FONT color="green">478</FONT>         *<a name="line.478"></a>
<FONT color="green">479</FONT>         * &lt;p&gt;<a name="line.479"></a>
<FONT color="green">480</FONT>         * &lt;table&gt;<a name="line.480"></a>
<FONT color="green">481</FONT>         *   &lt;tr&gt;<a name="line.481"></a>
<FONT color="green">482</FONT>         *     &lt;td valign=top&gt;<a name="line.482"></a>
<FONT color="green">483</FONT>         *       &lt;b&gt;Precondition&lt;/b&gt;:<a name="line.483"></a>
<FONT color="green">484</FONT>         *     &lt;/td&gt;<a name="line.484"></a>
<FONT color="green">485</FONT>         *     &lt;td valign=top&gt;<a name="line.485"></a>
<FONT color="green">486</FONT>         *       none<a name="line.486"></a>
<FONT color="green">487</FONT>         *     &lt;/td&gt;<a name="line.487"></a>
<FONT color="green">488</FONT>         *     &lt;td valign=top&gt;<a name="line.488"></a>
<FONT color="green">489</FONT>         *     &lt;/td&gt;<a name="line.489"></a>
<FONT color="green">490</FONT>         *   &lt;/tr&gt;<a name="line.490"></a>
<FONT color="green">491</FONT>         *   &lt;tr&gt;<a name="line.491"></a>
<FONT color="green">492</FONT>         *     &lt;td valign=top&gt;<a name="line.492"></a>
<FONT color="green">493</FONT>         *       &lt;b&gt;Postcondition&lt;/b&gt;:<a name="line.493"></a>
<FONT color="green">494</FONT>         *     &lt;/td&gt;<a name="line.494"></a>
<FONT color="green">495</FONT>         *     &lt;td valign=top&gt;<a name="line.495"></a>
<FONT color="green">496</FONT>         *       &lt;i&gt;file&lt;/i&gt; = &lt;i&gt;file'&lt;/i&gt;[n..|&lt;i&gt;file'&lt;/i&gt;|-1] &lt;br/&gt;<a name="line.496"></a>
<FONT color="green">497</FONT>         *       &amp;forall; (0 &amp;lt;= i AND i &amp;lt; n &amp;rArr; isWhitespace(file'[i]))<a name="line.497"></a>
<FONT color="green">498</FONT>         *       &lt;br/&gt;<a name="line.498"></a>
<FONT color="green">499</FONT>         *       &amp;not; isWhitespace(file'[n])<a name="line.499"></a>
<FONT color="green">500</FONT>         *     &lt;/td&gt;<a name="line.500"></a>
<FONT color="green">501</FONT>         *     &lt;td valign=top&gt;<a name="line.501"></a>
<FONT color="green">502</FONT>         *       AND &lt;br/&gt;<a name="line.502"></a>
<FONT color="green">503</FONT>         *       AND &lt;br/&gt;<a name="line.503"></a>
<FONT color="green">504</FONT>         *       &amp;nbsp;<a name="line.504"></a>
<FONT color="green">505</FONT>         *     &lt;/td&gt;<a name="line.505"></a>
<FONT color="green">506</FONT>         *   &lt;/tr&gt;<a name="line.506"></a>
<FONT color="green">507</FONT>         * &lt;/table&gt;<a name="line.507"></a>
<FONT color="green">508</FONT>         * @see &lt;a href="../../srchtml/lex/Lex.html#skipWhitespace"&gt;Source Code&lt;/a&gt;<a name="line.508"></a>
<FONT color="green">509</FONT>         */<a name="line.509"></a>
<FONT color="green">510</FONT>        protected void skipWhiteSpace()<a name="line.510"></a>
<FONT color="green">511</FONT>        {<a name="line.511"></a>
<FONT color="green">512</FONT>            while(Character.isWhitespace(file.front())){<a name="line.512"></a>
<FONT color="green">513</FONT>                file.popFront();<a name="line.513"></a>
<FONT color="green">514</FONT>            };<a name="line.514"></a>
<FONT color="green">515</FONT>        }<a name="line.515"></a>
<FONT color="green">516</FONT>    <a name="line.516"></a>
<FONT color="green">517</FONT>    <a name="line.517"></a>
<FONT color="green">518</FONT>        /**<a name="line.518"></a>
<FONT color="green">519</FONT>         * Gets a String Token.  A string token begins with a "'" followed by<a name="line.519"></a>
<FONT color="green">520</FONT>         * zero or more characters and is terminated by a matching "'".  A "'"<a name="line.520"></a>
<FONT color="green">521</FONT>         * can show up inside a string if it is represented as a double single <a name="line.521"></a>
<FONT color="green">522</FONT>         * quote "''".<a name="line.522"></a>
<FONT color="green">523</FONT>         *<a name="line.523"></a>
<FONT color="green">524</FONT>         * &lt;p&gt;<a name="line.524"></a>
<FONT color="green">525</FONT>         * &lt;table&gt;<a name="line.525"></a>
<FONT color="green">526</FONT>         *   &lt;tr&gt;<a name="line.526"></a>
<FONT color="green">527</FONT>         *     &lt;td valign=top&gt;<a name="line.527"></a>
<FONT color="green">528</FONT>         *       &lt;b&gt;Precondition&lt;/b&gt;:<a name="line.528"></a>
<FONT color="green">529</FONT>         *     &lt;/td&gt;<a name="line.529"></a>
<FONT color="green">530</FONT>         *     &lt;td valign=top&gt;<a name="line.530"></a>
<FONT color="green">531</FONT>         *       &lt;i&gt;file&lt;/i&gt;.front() = '\'' &lt;br/&gt;<a name="line.531"></a>
<FONT color="green">532</FONT>         *       this is the beginning of a terminated string.<a name="line.532"></a>
<FONT color="green">533</FONT>         *     &lt;/td&gt;<a name="line.533"></a>
<FONT color="green">534</FONT>         *     &lt;td valign=top&gt;<a name="line.534"></a>
<FONT color="green">535</FONT>         *       AND &lt;br/&gt;<a name="line.535"></a>
<FONT color="green">536</FONT>         *       &amp;nbsp;<a name="line.536"></a>
<FONT color="green">537</FONT>         *     &lt;/td&gt;<a name="line.537"></a>
<FONT color="green">538</FONT>         *   &lt;/tr&gt;<a name="line.538"></a>
<FONT color="green">539</FONT>         *   &lt;tr&gt;<a name="line.539"></a>
<FONT color="green">540</FONT>         *     &lt;td valign=top&gt;<a name="line.540"></a>
<FONT color="green">541</FONT>         *       &lt;b&gt;Postcondition&lt;/b&gt;:<a name="line.541"></a>
<FONT color="green">542</FONT>         *     &lt;/td&gt;<a name="line.542"></a>
<FONT color="green">543</FONT>         *     &lt;td valign=top&gt;<a name="line.543"></a>
<FONT color="green">544</FONT>         *       result = new Token(TokenType.STRING,<a name="line.544"></a>
<FONT color="green">545</FONT>         *                                   &lt;i&gt;file&lt;/i&gt;'[1..n-1],<a name="line.545"></a>
<FONT color="green">546</FONT>         *                                   &lt;i&gt;file&lt;/i&gt;'.getLineNumber())  &lt;br/&gt;<a name="line.546"></a>
<FONT color="green">547</FONT>         *                &lt;i&gt;file&lt;/i&gt; = &lt;i&gt;file&lt;/i&gt;'[n+1..|&lt;i&gt;file&lt;/i&gt;'-1|] &lt;br/&gt;<a name="line.547"></a>
<FONT color="green">548</FONT>         *                &lt;i&gt;file&lt;/i&gt;'[n] = "'"                             &lt;br/&gt;<a name="line.548"></a>
<FONT color="green">549</FONT>         *                Every "'" in &lt;i&gt;file&lt;/i&gt;'[1..n-1] must be part of a<a name="line.549"></a>
<FONT color="green">550</FONT>         *                double quote<a name="line.550"></a>
<FONT color="green">551</FONT>         *     &lt;/td&gt;<a name="line.551"></a>
<FONT color="green">552</FONT>         *     &lt;td valign=top&gt;<a name="line.552"></a>
<FONT color="green">553</FONT>         *       AND &lt;br/&gt;<a name="line.553"></a>
<FONT color="green">554</FONT>         *       AND &lt;br/&gt;<a name="line.554"></a>
<FONT color="green">555</FONT>         *       AND &lt;br/&gt;<a name="line.555"></a>
<FONT color="green">556</FONT>         *       &amp;nbsp;<a name="line.556"></a>
<FONT color="green">557</FONT>         *     &lt;/td&gt;<a name="line.557"></a>
<FONT color="green">558</FONT>         *   &lt;/tr&gt;<a name="line.558"></a>
<FONT color="green">559</FONT>         * &lt;/table&gt;<a name="line.559"></a>
<FONT color="green">560</FONT>         *<a name="line.560"></a>
<FONT color="green">561</FONT>         * @throws ParserException -- When we find an unterminated String.<a name="line.561"></a>
<FONT color="green">562</FONT>         *<a name="line.562"></a>
<FONT color="green">563</FONT>         * @return the token containing the string found<a name="line.563"></a>
<FONT color="green">564</FONT>         * @see &lt;a href="../../srchtml/lex/Lex.html#getConstant"&gt;Source Code&lt;/a&gt;<a name="line.564"></a>
<FONT color="green">565</FONT>         */<a name="line.565"></a>
<FONT color="green">566</FONT>        protected Constant getConstant()<a name="line.566"></a>
<FONT color="green">567</FONT>            throws ParserException<a name="line.567"></a>
<FONT color="green">568</FONT>        {<a name="line.568"></a>
<FONT color="green">569</FONT>            //PreCondition: file.front() == '\''<a name="line.569"></a>
<FONT color="green">570</FONT>            int line = file.getLineNumber();<a name="line.570"></a>
<FONT color="green">571</FONT>            if(file.front() != '\'')<a name="line.571"></a>
<FONT color="green">572</FONT>                throw new ParserException("Error on line " + line + ".\n" +<a name="line.572"></a>
<FONT color="green">573</FONT>                                    "A string must start with a '.");<a name="line.573"></a>
<FONT color="green">574</FONT>    <a name="line.574"></a>
<FONT color="green">575</FONT>    <a name="line.575"></a>
<FONT color="green">576</FONT>            file.popFront(); // throw away the leading quote<a name="line.576"></a>
<FONT color="green">577</FONT>    <a name="line.577"></a>
<FONT color="green">578</FONT>            StringBuffer result = new StringBuffer();<a name="line.578"></a>
<FONT color="green">579</FONT>            boolean foundEnd = false;<a name="line.579"></a>
<FONT color="green">580</FONT>            while(!foundEnd &amp;&amp; file.front() != file.EOF){<a name="line.580"></a>
<FONT color="green">581</FONT>                if(file.front() == '\''){<a name="line.581"></a>
<FONT color="green">582</FONT>                    file.popFront();<a name="line.582"></a>
<FONT color="green">583</FONT>                    if(file.front() == '\''){  //found a legal double quote<a name="line.583"></a>
<FONT color="green">584</FONT>                        result.append('\'');<a name="line.584"></a>
<FONT color="green">585</FONT>                        file.popFront();<a name="line.585"></a>
<FONT color="green">586</FONT>                    } else {<a name="line.586"></a>
<FONT color="green">587</FONT>                        foundEnd = true;       //found the end of the quote<a name="line.587"></a>
<FONT color="green">588</FONT>                    };<a name="line.588"></a>
<FONT color="green">589</FONT>                } else {<a name="line.589"></a>
<FONT color="green">590</FONT>                    result.append(file.front());<a name="line.590"></a>
<FONT color="green">591</FONT>                    file.popFront();<a name="line.591"></a>
<FONT color="green">592</FONT>                };<a name="line.592"></a>
<FONT color="green">593</FONT>            };<a name="line.593"></a>
<FONT color="green">594</FONT>           <a name="line.594"></a>
<FONT color="green">595</FONT>            Constant resultToken = null;<a name="line.595"></a>
<FONT color="green">596</FONT>            if(foundEnd){<a name="line.596"></a>
<FONT color="green">597</FONT>                resultToken = new Constant(result.toString(),line);<a name="line.597"></a>
<FONT color="green">598</FONT>            } else {<a name="line.598"></a>
<FONT color="green">599</FONT>                throw new ParserException("Error on line " + line + ".\n" +<a name="line.599"></a>
<FONT color="green">600</FONT>                                    "Unterminated string found");<a name="line.600"></a>
<FONT color="green">601</FONT>            };<a name="line.601"></a>
<FONT color="green">602</FONT>            return resultToken;<a name="line.602"></a>
<FONT color="green">603</FONT>        }<a name="line.603"></a>
<FONT color="green">604</FONT>    <a name="line.604"></a>
<FONT color="green">605</FONT>        /**<a name="line.605"></a>
<FONT color="green">606</FONT>         * Create an identifier Token (if it is actually a keyword, convert it<a name="line.606"></a>
<FONT color="green">607</FONT>         * to a keyword).  The key words are: "Schemes", "Facts", "Rules", and<a name="line.607"></a>
<FONT color="green">608</FONT>         * "Queries".  Keywords are case insensitive.<a name="line.608"></a>
<FONT color="green">609</FONT>         *<a name="line.609"></a>
<FONT color="green">610</FONT>         * @return the identifier or keyword found<a name="line.610"></a>
<FONT color="green">611</FONT>         *<a name="line.611"></a>
<FONT color="green">612</FONT>         * &lt;p&gt;<a name="line.612"></a>
<FONT color="green">613</FONT>         * &lt;table&gt;<a name="line.613"></a>
<FONT color="green">614</FONT>         *   &lt;tr&gt;<a name="line.614"></a>
<FONT color="green">615</FONT>         *     &lt;td valign=top&gt;<a name="line.615"></a>
<FONT color="green">616</FONT>         *       &lt;b&gt;Precondition&lt;/b&gt;:<a name="line.616"></a>
<FONT color="green">617</FONT>         *     &lt;/td&gt;<a name="line.617"></a>
<FONT color="green">618</FONT>         *     &lt;td valign=top&gt;<a name="line.618"></a>
<FONT color="green">619</FONT>         *       isLetter(&lt;i&gt;tokens&lt;/i&gt;[0])<a name="line.619"></a>
<FONT color="green">620</FONT>         *     &lt;/td&gt;<a name="line.620"></a>
<FONT color="green">621</FONT>         *     &lt;td valign=top&gt;<a name="line.621"></a>
<FONT color="green">622</FONT>         *     &lt;/td&gt;<a name="line.622"></a>
<FONT color="green">623</FONT>         *   &lt;/tr&gt;<a name="line.623"></a>
<FONT color="green">624</FONT>         *   &lt;tr&gt;<a name="line.624"></a>
<FONT color="green">625</FONT>         *     &lt;td valign=top&gt;<a name="line.625"></a>
<FONT color="green">626</FONT>         *       &lt;b&gt;Postcondition&lt;/b&gt;:<a name="line.626"></a>
<FONT color="green">627</FONT>         *     &lt;/td&gt;<a name="line.627"></a>
<FONT color="green">628</FONT>         *     &lt;td valign=top&gt;<a name="line.628"></a>
<FONT color="green">629</FONT>         *       &lt;i&gt;file&lt;/i&gt; = &lt;i&gt;file'&lt;/i&gt;[n..|&lt;i&gt;file'&lt;/i&gt;|-1]      &lt;br/&gt;<a name="line.629"></a>
<FONT color="green">630</FONT>         *     &lt;/td&gt;<a name="line.630"></a>
<FONT color="green">631</FONT>         *     &lt;td&gt;<a name="line.631"></a>
<FONT color="green">632</FONT>         *       AND<a name="line.632"></a>
<FONT color="green">633</FONT>         *     &lt;/td&gt;<a name="line.633"></a>
<FONT color="green">634</FONT>         *   &lt;/tr&gt;<a name="line.634"></a>
<FONT color="green">635</FONT>         *   &lt;tr&gt;<a name="line.635"></a>
<FONT color="green">636</FONT>         *     &lt;td&gt;&amp;nbsp;&lt;/td&gt;<a name="line.636"></a>
<FONT color="green">637</FONT>         *     &lt;td&gt;<a name="line.637"></a>
<FONT color="green">638</FONT>         *       &amp;forall;&lt;sub&gt;i&lt;/sub&gt; (1 &amp;lt;= i AND i &amp;lt; n &amp;rArr;<a name="line.638"></a>
<FONT color="green">639</FONT>         *           isLetterOrDigit(&lt;i&gt;file&lt;/i&gt;[i])<a name="line.639"></a>
<FONT color="green">640</FONT>         *     &lt;/td&gt;<a name="line.640"></a>
<FONT color="green">641</FONT>         *     &lt;td&gt;<a name="line.641"></a>
<FONT color="green">642</FONT>         *       AND<a name="line.642"></a>
<FONT color="green">643</FONT>         *     &lt;/td&gt;<a name="line.643"></a>
<FONT color="green">644</FONT>         *   &lt;/tr&gt;<a name="line.644"></a>
<FONT color="green">645</FONT>         *   &lt;tr&gt;<a name="line.645"></a>
<FONT color="green">646</FONT>         *     &lt;td&gt;&amp;nbsp;&lt;/td&gt;<a name="line.646"></a>
<FONT color="green">647</FONT>         *     &lt;td&gt;<a name="line.647"></a>
<FONT color="green">648</FONT>         *       &amp;not; isLetterOrDigit(&lt;i&gt;file&lt;/i&gt;[n])                  &lt;br/&gt;<a name="line.648"></a>
<FONT color="green">649</FONT>         *     &lt;/td&gt;<a name="line.649"></a>
<FONT color="green">650</FONT>         *     &lt;td&gt;<a name="line.650"></a>
<FONT color="green">651</FONT>         *       AND<a name="line.651"></a>
<FONT color="green">652</FONT>         *     &lt;/td&gt;<a name="line.652"></a>
<FONT color="green">653</FONT>         *   &lt;/tr&gt;<a name="line.653"></a>
<FONT color="green">654</FONT>         *   &lt;tr&gt;<a name="line.654"></a>
<FONT color="green">655</FONT>         *     &lt;td&gt;&amp;nbsp;&lt;/td&gt;<a name="line.655"></a>
<FONT color="green">656</FONT>         *     &lt;td&gt;<a name="line.656"></a>
<FONT color="green">657</FONT>         *       str = &lt;i&gt;file'&lt;/i&gt;[0..n-1]                           &lt;br/&gt;<a name="line.657"></a>
<FONT color="green">658</FONT>         *     &lt;/td&gt;<a name="line.658"></a>
<FONT color="green">659</FONT>         *     &lt;td&gt;<a name="line.659"></a>
<FONT color="green">660</FONT>         *       AND<a name="line.660"></a>
<FONT color="green">661</FONT>         *     &lt;/td&gt;<a name="line.661"></a>
<FONT color="green">662</FONT>         *   &lt;/tr&gt;<a name="line.662"></a>
<FONT color="green">663</FONT>         *   &lt;tr&gt;<a name="line.663"></a>
<FONT color="green">664</FONT>         *     &lt;td&gt;&amp;nbsp;&lt;/td&gt;<a name="line.664"></a>
<FONT color="green">665</FONT>         *     &lt;td&gt;<a name="line.665"></a>
<FONT color="green">666</FONT>         *       line = file'.getLineNumber()                         &lt;br/&gt;<a name="line.666"></a>
<FONT color="green">667</FONT>         *     &lt;/td&gt;<a name="line.667"></a>
<FONT color="green">668</FONT>         *     &lt;td&gt;<a name="line.668"></a>
<FONT color="green">669</FONT>         *       AND<a name="line.669"></a>
<FONT color="green">670</FONT>         *     &lt;/td&gt;<a name="line.670"></a>
<FONT color="green">671</FONT>         *   &lt;/tr&gt;<a name="line.671"></a>
<FONT color="green">672</FONT>         *   &lt;tr&gt;<a name="line.672"></a>
<FONT color="green">673</FONT>         *     &lt;td&gt;&amp;nbsp;&lt;/td&gt;<a name="line.673"></a>
<FONT color="green">674</FONT>         *     &lt;td&gt;<a name="line.674"></a>
<FONT color="green">675</FONT>         *       str.equalsIgnoreCase("Schemes") &amp;rArr;<a name="line.675"></a>
<FONT color="green">676</FONT>         *       result = new Token(TokenType.SCHEMES, str, line) &lt;br/&gt;<a name="line.676"></a>
<FONT color="green">677</FONT>         *     &lt;/td&gt;<a name="line.677"></a>
<FONT color="green">678</FONT>         *     &lt;td&gt;<a name="line.678"></a>
<FONT color="green">679</FONT>         *       AND<a name="line.679"></a>
<FONT color="green">680</FONT>         *     &lt;/td&gt;<a name="line.680"></a>
<FONT color="green">681</FONT>         *   &lt;/tr&gt;<a name="line.681"></a>
<FONT color="green">682</FONT>         *   &lt;tr&gt;<a name="line.682"></a>
<FONT color="green">683</FONT>         *     &lt;td&gt;&amp;nbsp;&lt;/td&gt;<a name="line.683"></a>
<FONT color="green">684</FONT>         *     &lt;td&gt;<a name="line.684"></a>
<FONT color="green">685</FONT>         *       str.equalsIgnoreCase("Facts") &amp;rArr;<a name="line.685"></a>
<FONT color="green">686</FONT>         *       result = new Token(TokenType.FACTS, str, line)   &lt;br/&gt;<a name="line.686"></a>
<FONT color="green">687</FONT>         *     &lt;/td&gt;<a name="line.687"></a>
<FONT color="green">688</FONT>         *     &lt;td&gt;<a name="line.688"></a>
<FONT color="green">689</FONT>         *       AND<a name="line.689"></a>
<FONT color="green">690</FONT>         *     &lt;/td&gt;<a name="line.690"></a>
<FONT color="green">691</FONT>         *   &lt;/tr&gt;<a name="line.691"></a>
<FONT color="green">692</FONT>         *   &lt;tr&gt;<a name="line.692"></a>
<FONT color="green">693</FONT>         *     &lt;td&gt;&amp;nbsp;&lt;/td&gt;<a name="line.693"></a>
<FONT color="green">694</FONT>         *     &lt;td&gt;<a name="line.694"></a>
<FONT color="green">695</FONT>         *       str.equalsIgnoreCase("Rules") &amp;rArr;<a name="line.695"></a>
<FONT color="green">696</FONT>         *       result = new Token(TokenType.RULES, str, line)   &lt;br/&gt;<a name="line.696"></a>
<FONT color="green">697</FONT>         *     &lt;/td&gt;<a name="line.697"></a>
<FONT color="green">698</FONT>         *     &lt;td&gt;<a name="line.698"></a>
<FONT color="green">699</FONT>         *       AND<a name="line.699"></a>
<FONT color="green">700</FONT>         *     &lt;/td&gt;<a name="line.700"></a>
<FONT color="green">701</FONT>         *   &lt;/tr&gt;<a name="line.701"></a>
<FONT color="green">702</FONT>         *   &lt;tr&gt;<a name="line.702"></a>
<FONT color="green">703</FONT>         *     &lt;td&gt;&amp;nbsp;&lt;/td&gt;<a name="line.703"></a>
<FONT color="green">704</FONT>         *     &lt;td&gt;<a name="line.704"></a>
<FONT color="green">705</FONT>         *       str.equalsIgnoreCase("Queries") &amp;rArr;<a name="line.705"></a>
<FONT color="green">706</FONT>         *       result = new Token(TokenType.QUERIES, str, line) &lt;br/&gt;<a name="line.706"></a>
<FONT color="green">707</FONT>         *     &lt;/td&gt;<a name="line.707"></a>
<FONT color="green">708</FONT>         *     &lt;td&gt;<a name="line.708"></a>
<FONT color="green">709</FONT>         *       AND<a name="line.709"></a>
<FONT color="green">710</FONT>         *     &lt;/td&gt;<a name="line.710"></a>
<FONT color="green">711</FONT>         *   &lt;/tr&gt;<a name="line.711"></a>
<FONT color="green">712</FONT>         *   &lt;tr&gt;<a name="line.712"></a>
<FONT color="green">713</FONT>         *     &lt;td&gt;&amp;nbsp;&lt;/td&gt;<a name="line.713"></a>
<FONT color="green">714</FONT>         *     &lt;td&gt;<a name="line.714"></a>
<FONT color="green">715</FONT>         *       otherwise &amp;rArr;<a name="line.715"></a>
<FONT color="green">716</FONT>         *       result = new Token(TokenType.ID, str, line) <a name="line.716"></a>
<FONT color="green">717</FONT>         *     &lt;/td&gt;<a name="line.717"></a>
<FONT color="green">718</FONT>         *   &lt;/tr&gt;<a name="line.718"></a>
<FONT color="green">719</FONT>         * &lt;/table&gt;<a name="line.719"></a>
<FONT color="green">720</FONT>         * @see &lt;a href="../../srchtml/lex/Lex.html#getId"&gt;Source Code&lt;/a&gt;<a name="line.720"></a>
<FONT color="green">721</FONT>         */<a name="line.721"></a>
<FONT color="green">722</FONT>        protected Token getIdentifierOrKeyword()<a name="line.722"></a>
<FONT color="green">723</FONT>            throws ParserException<a name="line.723"></a>
<FONT color="green">724</FONT>        {<a name="line.724"></a>
<FONT color="green">725</FONT>    <a name="line.725"></a>
<FONT color="green">726</FONT>            //The string may cover many lines, but, the lineNumber of the token<a name="line.726"></a>
<FONT color="green">727</FONT>            //is where the token starts. So, we get the lineNumber before we do<a name="line.727"></a>
<FONT color="green">728</FONT>            //anything else.<a name="line.728"></a>
<FONT color="green">729</FONT>            int line = file.getLineNumber();<a name="line.729"></a>
<FONT color="green">730</FONT>    <a name="line.730"></a>
<FONT color="green">731</FONT>            StringBuffer result = new StringBuffer();<a name="line.731"></a>
<FONT color="green">732</FONT>            while(Character.isLetterOrDigit(file.front())){<a name="line.732"></a>
<FONT color="green">733</FONT>                result.append(file.front());<a name="line.733"></a>
<FONT color="green">734</FONT>                file.popFront();<a name="line.734"></a>
<FONT color="green">735</FONT>            };<a name="line.735"></a>
<FONT color="green">736</FONT>                <a name="line.736"></a>
<FONT color="green">737</FONT>            String value = result.toString(); <a name="line.737"></a>
<FONT color="green">738</FONT>    <a name="line.738"></a>
<FONT color="green">739</FONT>            //This checks to see if the identifier is actually a key word.:wq<a name="line.739"></a>
<FONT color="green">740</FONT>            Token resultToken = null;<a name="line.740"></a>
<FONT color="green">741</FONT>            if(value.equalsIgnoreCase("Schemes")){<a name="line.741"></a>
<FONT color="green">742</FONT>                resultToken = new Token(TokenType.SCHEMES, value, line);<a name="line.742"></a>
<FONT color="green">743</FONT>            } else if(value.equalsIgnoreCase("Facts")){<a name="line.743"></a>
<FONT color="green">744</FONT>                resultToken = new Token(TokenType.FACTS, value, line);<a name="line.744"></a>
<FONT color="green">745</FONT>            } else if(value.equalsIgnoreCase("Rules")){<a name="line.745"></a>
<FONT color="green">746</FONT>                resultToken = new Token(TokenType.RULES, value, line);<a name="line.746"></a>
<FONT color="green">747</FONT>            } else if(value.equalsIgnoreCase("Queries")){<a name="line.747"></a>
<FONT color="green">748</FONT>                resultToken = new Token(TokenType.QUERIES, value, line);<a name="line.748"></a>
<FONT color="green">749</FONT>            } else {<a name="line.749"></a>
<FONT color="green">750</FONT>                resultToken = new Identifier(value, line);<a name="line.750"></a>
<FONT color="green">751</FONT>            };<a name="line.751"></a>
<FONT color="green">752</FONT>    <a name="line.752"></a>
<FONT color="green">753</FONT>            return resultToken;<a name="line.753"></a>
<FONT color="green">754</FONT>        }<a name="line.754"></a>
<FONT color="green">755</FONT>    }<a name="line.755"></a>




























































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